31,549 research outputs found

    LS Penrose’s limit theorem: Tests by simulation

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    LS Penrose’s limit theorem (PLT) – which is implicit in Penrose [5, p. 72] and for which he gave no rigorous proof – says that, in simple weighted voting games, if the number of voters increases indefinitely while existing voters retain their weights and the relative quota is pegged, then – under certain conditions – the ratio between the voting powers of any two voters converges to the ratio between their weights. Lindner and Machover [3] prove some special cases of PLT; and conjecture that the theorem holds, under rather general conditions, for large classes of weighted voting games, various values of the quota, and with respect to several measures of voting power. We use simulation to test this conjecture. It is corroborated w.r.t. the Penrose–Banzhaf index for a quota of 50% but not for other values; w.r.t. the Shapley–Shubik index the conjecture is corroborated for all values of the quota (short of 100%).limit theorems, majority games, simulation, weighted voting games

    Distributed MPC for coordinated energy efficiency utilization in microgrid systems

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    To improve the renewable energy utilization of distributed microgrid systems, this paper presents an optimal distributed model predictive control strategy to coordinate energy management among microgrid systems. In particular, through information exchange among systems, each microgrid in the network, which includes renewable generation, storage systems, and some controllable loads, can maintain its own systemwide supply and demand balance. With our mechanism, the closed-loop stability of the distributed microgrid systems can be guaranteed. In addition, we provide evaluation criteria of renewable energy utilization to validate our proposed method. Simulations show that the supply demand balance in each microgrid is achieved while, at the same time, the system operation cost is reduced, which demonstrates the effectiveness and efficiency of our proposed policy.Accepted manuscrip

    Scalable solid-state quantum computation in decoherence-free subspaces with trapped ions

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    We propose a decoherence-free subspaces (DFS) scheme to realize scalable quantum computation with trapped ions. The spin-dependent Coulomb interaction is exploited, and the universal set of unconventional geometric quantum gates is achieved in encoded subspaces that are immune from decoherence by collective dephasing. The scalability of the scheme for the ion array system is demonstrated, either by an adiabatic way of switching on and off the interactions, or by a fast gate scheme with comprehensive DFS encoding and noise decoupling techniques.Comment: 4 pages, 1 figur

    A metal–organic framework/α-alumina composite with a novel geometry for enhanced adsorptive separation

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    The development of a metal–organic framework/α-alumina composite leads to a novel concept: efficient adsorption occurs within a plurality of radial micro-channels with no loss of the active adsorbents during the process. This composite can effectively remediate arsenic contaminated water producing potable water recovery, whereas the conventional fixed bed requires eight times the amount of active adsorbents to achieve a similar performance

    Theoretical studies of the local structures and EPR parameters for Cu2+^{2+} center in Cd2_{2}(NH4_{4})2_{2}(SO4_{4})3_{3} single crystal

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    The electron paramagnetic resonance (EPR) parameters (gg factors gig_{i} and the hyperfine structure constants Ai{{A}}_{{i}}, i=x,y,z{i} = {x}, {y}, {z}) are interpreted by using the perturbation formulae for a 3d93{d}^{9} ion in rhombically ({D}2h_{2h}) elongated octahedra. In the calculated formulae, the crystal field parameters are set up from the superposition model, and the contribution to the EPR parameters from the admixture of dd-orbitals in the ground state wave function of the Cu2+^{2+} ion was taken into account. Based on the calculation, local structural parameters of the impurity Cu2+^{2+} center in Cd2_{2}(NH4_{4})2_{2}(SO4_{4})3_{3} (CAS) crystal were obtained (i.e., Rx2.05{R}_{{x}}\approx 2.05 {\AA}, Ry1.91{R}_{{y}} \approx 1.91 {\AA}, Rz2.32{R}_{{z}} \approx 2.32 {\AA}). The theoretical EPR parameters based on the above Cu2+^{2+}-O2^{2-} bond lengths in CAS crystal show a good agreement with the observed values. The results are discussed.Comment: 5 page

    A salient and task-irrelevant collinear structure hurts visual search

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    Une Etude Comparée de L’oralité et de L’écriture Dans La Littérature Africaine D’expression Française: Le Cas Des Romans d’Ahmadou Kourouma

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    Il n’est plus possible aujourd’hui que l’oralité et l’écriture s’ignorent, bien que l’oralité ait existé pendant longtemps dans la société traditionnelle africaine. La raison est qu’il n’existe plus une société traditionnelle à l’état pur. La plupart des membres de cette société ont fréquenté l’école de type européen, ils ont séjourné en ville et ont également eu des contacts avec une langue européenne ou une autre liée à l’écriture. Les fervents de l’instruction scolaire se sont aussi rendus compte des limites de l’écriture et ont voulu bien retrouver certaines valeurs de la société traditionnelle africaine. Cependant, il convient ici de savoir que le message de la tradition orale est certainement au carrefour de deux axes : l’émetteur-récepteur et la tradition-situation. Par ailleurs, on constate également que le message écrit aussi est au carrefour de deux axes, mais ces axes sont nettement différents de ceux de la tradition orale. C’est à cet égard que dans ce travail, nous allons examiner de près les deux axes et voir leurs conséquences sur chacun d’eux

    Key factors and network model for location-based cultural mobile game design

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    The use of smart devices as media for digital learning constitutes a new-generation digital learning paradigm. Therefore, context-aware game-based learning has attracted considerable attention. Location-based games have not only positive effects on learning but also pronounced effects on culture and history. Accordingly, focusing on railway cultural heritages, we attempted to assess interdependent relationships between key factors crucial for the design of a location-based mobile game for cultural heritages. We adopted the analytic network process (ANP) for our assessment. We initially performed a literature review to generalize relevant criteria and elements and developed a questionnaire based on the fuzzy delphi method (FDM); which lead to the selection of key factors, namely 3 criteria and 15 elements. We also applied an online ANP-based questionnaire; on the basis of the experts' opinions, we established a network model and determined the priority order of the key factors. The results revealed that experts considered “culture learning” to be of the highest importance, with the most important three elements being “prior knowledge,” “challenge levels,” and “cultural narrative.” Moreover, culture learning exhibited a strong interaction with content design. In addition, each element had a considerable influence on the remaining elements that could provide references for the construction of location-based cultural mobile games in the future

    Electrooptic and electroabsorptive modulation properties in interdiffusion-modified AlGaAs-GaAs quantum wells

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    The electric field induced refractive index change and absorption coefficient change in TE polarization are analyzed at room temperature for several interdiffusion modified Al0.3Ga0.7As-GaAs quantum-well structures. The results show that for the small and medium interdiffusion lengths with fields of 100 and 50 kV/cm, respectively, improved chirping and electroabsorption can be obtained. Further, in a selected set of interdiffusion lengths and fields, the material can be used for an electroabsorption modulator with reduced chirping in a wide range of operation wavelengths (758-874 nm).published_or_final_versio

    On differential uniformity of maps that may hide an algebraic trapdoor

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    We investigate some differential properties for permutations in the affine group, of a vector space V over the binary field, with respect to a new group operation \circ, inducing an alternative vector space structure on VV .Comment: arXiv admin note: text overlap with arXiv:1411.768
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